The present invention relates generally to integrated circuits, and, more particularly, to a synchronous clock divider integrated circuit.
Integrated circuits (ICs) include many sequential elements such as flip-flops, and latches. The frequency of operation of the sequential elements is governed by the cycling rate of clock signals. Duty cycle is an ON period of a single cycle of a clock signal. The duty cycle represents the ON time of a clock signal supplied to sequential elements. The cycling rate of the clock signals may be changed by changing divide ratios of clock divider circuit. The divide ratio is used to change the clock frequency of the clock signals.
Aging of sequential elements (silicon aging) and chip variations (e.g., due to process, voltage and temperature) may result in duty cycle degradation, thereby affecting data paths inside the ICs. Aging-induced duty cycle shift may occur in a particular direction (increased fall-delays or increased rise delays) depending on types of asymmetric components in a clock tree topology.
Therefore, control over the duty cycle is required to compensate for duty cycle degradation. Further, duty cycle of a clock signal may also be changed to provide timing relaxation of half cycle paths.